1. Field of the Invention
The present invention relates to an aluminum nitride sintered body having a high breakdown voltage particularly suited to the requirements of high integration of a circuit board, and a method of preparing the same.
2. Description of the Background Art
An aluminum nitride sintered body having a high thermal conductivity is used as a radiating material such as a substrate for a semiconductor device or a circuit board, for example. At present, the high integration of circuit boards is being developed in order to cope with high speed processing of mass data and miniaturization of information processing equipment. A material for such a highly integrated circuit board must have an excellent radiating property in order to cope with the heat generated by high integration, and must have a high breakdown voltage in order to cope with the narrow spaces existing between circuit wires.
An aluminum nitride sintered body is being considered with interest as an excellent radiating substrate material, due to its high thermal conductivity. A conventional aluminum nitride sintered body has a breakdown voltage of about 10 to 20 kV/mm. Thus, what is still awaited in the field is an aluminum nitride sintered body, which is applicable to a highly integrated circuit board and which has a high breakdown voltage of at least 20 kV/mm.